Sewing Machine Modifications

[S. Heslop]

I want to attempt to extend and "modernise" an old sewing machine for the sake of thread painting/ free motion embroidery.

I replied to a classified ad yesterday to pick up a mystery Singer and a mystery Alfa machine. I was interested in the Singer since i've been doing some reading on them (and boy is it hard to find good information on sewing machines) and was thinking it was part of the 600 series from the photo. Which It was - a 611G. There's not much information on those online but the gist I got from reading is that Singer was cutting costs by the 600 series with plastic gears, as well as adding the bizarre and tempramental 'touch and sew' system of threading the bobbin. So it's a surprise that the 611G has the old style drop in bobbins, as well as metal gears inside.

Part of that reading up on machines was an attempt to find the ideal candidate to butcher. I was after a zig-zag machine with a top loading bobbin, rotary hook, and something rugged enough to survive running full blast for hours on end. Just that 611G seems too nice to cut up...

The Alfa machine was also included in the listing. It's hand cranked and not quite as exciting. But seems pretty durable and i'd feel alot better cutting it up.






This uses a side loading oscillating hook. I'm not a big fan of them since I find the bobbin case fiddly to load. Thread painting involves alot of switching threads out for different colours.

The 3 arms at the top and bottom of this picture deal with the feed dogs, and I don't need those for free motion stuff so they can go. It'd also let me cut out more of the frame around the hook to make it easier to access.


The top end is nice and simple.


Everything on that main shaft is held on with set screws, except for this crank in the end. Which is unfortunately the crank that drives the oscillating hook.


And here's the needle bar area.



By 'modernise' I mostly mean adding the conveniences from newer machines I quite like. Such as a slotted take up lever, guides to make threading alot faster and simpler, an automatic needle threader, motor stopping automatically at the needle up position, etc. I'm not fussed about this machine being at all useful for regular sewing though, just this one specific job.


But for extending it... replacing the shafts and links won't be a problem. I could make a coupler for that crank end onto a longer shaft since the yoke behind it is only for the feed dogs. The problem i've got is how to extend the frame itself. I believe it's cast iron and welding that seems to be a hit and miss thing from what i've read and I lack any brazing stuff. Only a cheap MIG welder and an AC only buzz box stick welder.

None of the sides are particularly parallel so just screwing plates on would be fiddly. I can't imagine id have much luck fabricating an entirely new frame either.

Guess the first thing to do will be to disassemble it so I can get a closer look at the frame.

[awemawson]

Welding or brazing will quite likely distort the existing shaft alignments so personally I'd avoid it.

Decide what you want extending, and bond it on with structural adhesive such as Belzona (expensive!) or Devcon metal filled putties to give a firm base augmented by screws drilled and tapped into the original casting.

[S. Heslop]

Welding or brazing will quite likely distort the existing shaft alignments so personally I'd avoid it.

Decide what you want extending, and bond it on with structural adhesive such as Belzona (expensive!) or Devcon metal filled putties to give a firm base augmented by screws drilled and tapped into the original casting.

Yeah you're right about distortions. I was thinking more of just giving it a go, since the backup plan was to cut out all the protrusions that act supports and bearings since they're all chunky enough to get a couple of screws in. With enough shims and swearing I might be able to get a welded steel frame to work, maybe. But I like that idea!

Got distracted cleaning up that Singer machine after finding out my point and shoot camera is dead. Possibly just the battery but its refusing to charge. I'll try find the stand-alone charger and spare battery, but I wanted to use it more for keeping track of what goes where in the Alfa machine without getting oil all over my phone.

[S. Heslop]

Got it pulled apart.


Here's most of the parts I'm gonna keep.




I think this is interesting, the thread tension assembly is the only part of the machine to use plastic and zinc. It'd also rotted and was stuck pretty fast.


Had to drill it out. I want to try adapt something else for the thread tension since this one was a bit fiddly to thread up.


Here's what i've currently got in mind but i'm a little unsure about it.



The idea is that there'll be studs with spacers/ stacks of washers and shims over them that'd give some adjustment to get it all lined up. I've got some... I think 5mm walled 50x100 box section steel hanging around from that terrible first attempt at a 3d printer, that I should be able to weld up into some sort of C channel shape.

It'd be nice if this didn't turn into an insane mess of braces, and it'd be nice to keep the weight down since it's already quite stout with the cast iron, but I'm not sure if that's going to be possible. Might be able to recover a bit of weight by cutting away all the cast iron I don't need, especially in the base.

Next step will be to strip the paint I think.

[hermetic]

Looks like an interesting project, many years ago I salvaged a Singer 29K from a local tip, and my brother still uses it for sewing leather, although he has several of them now. You will have to be careful to get the needle to shuttle timing exactly right, or it will smash needles like a good un!
Phil.

[S. Heslop]

Thanks!

I'm still fussing about how to try extending this. I've also measured the shafts and found them to be some fairly bizarre sizes that don't really line up with anything, in metric or imperial. The one shaft I was hoping to fully replace is around 0.370" and I can't see myself turning a long bar down successfully on my little lathe, but I can see myself maybe getting an adjustable reamer to work in making an extension. Even if that's not a great solution.

This is just starting to feel incredibly kludged before i've even made a cut. But I'll give it another day of thought before I just slice the thing in twain and work from there.

[S. Heslop]

In tapping the front bearing block out with a screwdriver i've gone and peened it enough that it wont come off the shaft. I didn't think I was hitting it that hard but I should've gotten the brass bar out sooner. I should also add that I'm planning to exend it out 5 inches, which is a fairly considerable span. I'm worried mostly about vibrations.

I'm picking my brother up from work tomorrow. Might ask his thoughts on welding cast iron. With that bearing block damaged I'm considering making an undersized replacement, with maybe a millimeter gap around it in the bore. But floating it in with epoxy/ epoxy putty. Alot of the stuff in the actual head itself beyond that is a somewhat loose fit so I think i'd have some room for a little misalignment.

[mattinker]

I can't see myself turning a long bar down successfully on my little lathe,

Simon,
couldn't you just turn down the ends where it counts?

Fun project, regards, Matthew

[WeldingRod]

I would avoid welding it!
Sneaky idea: clean both side around you cut line, and mould steel filled epoxy surfaces.  Ideally use some setscrews and screws to get flat plates positioned parallel to the machine shafts.  Drilling and tapping holes on both sides is worth the effort, and will help keep the epoxy in place.  And, cast in alignment key slots.  Then cut it in half.
That way you have true surfaces to work off of after cutting.  Think in terms of bedding an action, if you speak gunsmithing...
Of, and dont forget mould release on the plates you cast against...

Sent from my SAMSUNG-SM-G891A using Tapatalk

[S. Heslop]

Simon,
couldn't you just turn down the ends where it counts?

Fun project, regards, Matthew

Good call! Thanks.

I would avoid welding it!
Sneaky idea: clean both side around you cut line, and mould steel filled epoxy surfaces.  Ideally use some setscrews and screws to get flat plates positioned parallel to the machine shafts.  Drilling and tapping holes on both sides is worth the effort, and will help keep the epoxy in place.  And, cast in alignment key slots.  Then cut it in half.
That way you have true surfaces to work off of after cutting.  Think in terms of bedding an action, if you speak gunsmithing...
Of, and dont forget mould release on the plates you cast against...

Sent from my SAMSUNG-SM-G891A using Tapatalk

Yeah trying to weld it doesn't seem like the best idea. I keep going back and forth on it though.

The trouble i've got is that i'm fairly under-equipped for making any accurate measurements or jigging it up well. The top of the casting though is sort of flat, except for the protrusons, so I might be able to work from that. Cut the thing in half, screw some precision angle iron onto the rear side into the top edge, then slide the front end about till the shaft spins freely and fix that with screws and epoxy.

[S. Heslop]

I'm thinking of going back to the drawing board on this. Had another look inside some of the machines i've got to compare features.

This is the Brother Super Ace 3

It's hard to find information on this machine, and impossible to find spares. This photo was from when I was trying to get at the heavily worn plastic presser foot lever, and getting the plastic shell off was quite a feat. Spares for that lever don't exist so I built the worn part up with epoxy putty, which seems to be holding. Wish I took more photos of the inside, I only took this one to show a friend how baffling it was. The needle bar and feed dog direction are moved by a stepper motor. Computerized machines make me uncomfortable since it's only a matter of time till some capacitor dries out or a semiconductor fails.

It's got a top loading rotary hook which is still my favorite style.


Here's a Janome something or other that belonged to my sister.


It's one of those cheap entry level machines and never worked well, and getting the bobbin case out is a nightmare. It's an oscillating hook so I don't think there'd be any hope of extending it. Like the Brother machine, and I assume any modern machine, it's a hassle to get the plastic shell off. There was a screw left over on reassembling it...

It's tempting to complain about cutting costs and to romanticize the old 'all metal' machines. There's definitely some wonderful ones out there. But it's also easy to forget that what might cost £20 used nowadays cost someone the equivalent of £2000 50 years ago. And there were plenty of lousy machines back then too. Like the Singer 285.


This is an Elna Lotus ZZ.


I'm pretty stoked about this machine. It's probably the nicest looking sewing machine im aware of.



The panels fold out so it stores very neatly.



It's got a top loading rotary hook too, except it's behind the needle. It's such a fiddle to get at that they've included this bobbin extractor. I assume Singer must've been sitting on a patent for the style that's in front of the needle since nobody else used it till about the 2000s.



Here it is inside. Not sure what the shell is made from. It's a heavy machine so i'm assuming it's some sort of zinc alloy.

The main reason i'm hung up on rotary hooks is that they're coupled with either a geared vertical shaft, or just a toothed belt like in this machine. I think that'd be a whole lot easier to work around than oscillating hooks with their cranks and linkages.



This is the best feature of the Lotus. It's tiny.

I've also become a bit of a collector, but it's from every machine kind of being terrible in its own way and only doing a couple of jobs well.



So my thoughts are that any sort of rotary hook machine where the bobbin doesn't move laterally might be alot easier to extend. Using a stepper motor and an encoder to handle moving the needle bar for the zig-zag would simply things alot for me, since electronics are easier to handle than a complicated mechanism. If the Alfa machine was a rotary hook i'd just cleave the head off and bolt it to a welded steel arm, and come up with something new (couple of pillow blocks) for the lower half since i'd only have the one shaft to deal with that can be joined with a toothed belt.

Or maybe i've just gotten a taste for blood and I want to murder more machines.

[awemawson]

Be an awful lot easier just to buy a long reach machine such as a 'Sail Makers Sewing Machine'. They do pop up on eBay from time to time.

[S. Heslop]

Be an awful lot easier just to buy a long reach machine such as a 'Sail Makers Sewing Machine'. They do pop up on eBay from time to time.

I was looking at them earlier but they tend to be pricey, have elaborate threading procedures (I guess for reliability at high speeds, while using such huge spools it doesn't matter as much), and the whole big clutch motor mounted under the table takes up alot of space. They're also generally not designed for quick access to the bobbin, having to tip the whole machine up. They also tend to be incredibly specialised to only one type of stitch, and I believe sailmaking stuff often goes for a 3 or 4 step zig-zag rather than a regular zig-zag but I could be wrong on that.

I do like the look of these Singer 457 ones though with rotary take up levers.



It's an option but i'm not a big fan of camping ebay hoping the right machine shows up at the right price.

[efrench]

This thread makes me want to open up my wife's Bernina

[S. Heslop]

This thread makes me want to open up my wife's Bernina

Haha. If you do take some pictures! I hear they're great machines.

[Will_D]

This thread makes me want to open up my wife's Bernina

Its a good job we don't have dirty minds on this site! 

Will

[S. Heslop]

Picked another machine up.


A Singer G105, made in Brazil. No idea what year it was made. If it was a GUN then i'd have endless books, resources, and teams of 'historians' to reference the serial number against - with detailed histories of every engineer involved in its development along with the specific factories that were subcontracted for each part. But alas this machine wasn't made to kill people.


It's got a drop in bobbin and a rotary hook.


Plastic gears. The lid was tricky to take off, requires flexing the plastic to clear it over stuff, which is rather odd. It's also clogged with a very sticky and viscous grease that makes some things hard to move.


This is one feature i'm not too keen on, for my purposes. A tilting needle bar rather than the swinging kind. It'll make it harder to add a needle threading hook.

The take up lever is slotted. Although oddly on the machine as is it never raises high enough to clear the cover, making it somewhat useless.


This is what I was after, and wasn't sure if this machine would have. A belt driven hook. That should make it alot easier to extend the bottom!


So the frame itself seems to be made out of zamak, as far as I can tell. It's heavy and grey but doesn't ring like cast iron. Very dull sounding when tapped. Doesn't scratch easily either. It seems theres a good spot to cleave the head though that'll have room for a few screws, which is a relief since soldering it sounds tricky.

Cant wait to hack saw through all that zamak!

[S. Heslop]

I've got some corrections to make! Firstly I didn't intend that as a dig at the firearm guys, I just wish other types of machines got as much enthusiasm. Also I'm not sure why I thought the thing would be cast from zamak, it's clearly cast iron. It just sounded duller than usual till all the stuff was taken off. And lastly I think you could thread into that slotted take up lever, just not when the needle is in the up position.

I've now got this mostly pulled apart.



Here's all the stuff i'm keeping.


And here's a close up where I think would be best to cleave the head.


There'd be enough casting there to get a few screws in.


I'll have to take some measurements next so I can figure out how to to build the frame.

[mattinker]

Wouldn't a diagonal cut work better?

Just a thought, regards, Matthew

[S. Heslop]

Wouldn't a diagonal cut work better?

Just a thought, regards, Matthew

I think the square cut would be easier to align. But it does mean i'm going to be cutting through more stuff this way.


Spent the last few days measuring all the important points and trying to design the new frame. Here's what i've got so far.



Bit of a jumble but i'm trying to make use of the material i've got. I think i'm good for everything but the zig-zag mechanism now.

The way that seemed easiest to me would be to copy what the computerized machines do, and have a stepper motor move the needle bar. But i'm aiming for about 1200 stitches per minute and i'm not sure if the average nema 17 would keep up with that...

[efrench]

It depends on the driver and microprocessor.  A Teensy 3.6 microprocessor using the TeensyStep library can do 300000 steps per second.

[awemawson]

. . . all very well but can a NEMA17 stepper motor keep up with that step rate, that was the point at issue 

[S. Heslop]

Just reassembled the head area of machine at nearly 4am, since i'd forgotten to actually measure the amount of travel on the rod that connects the needle bar to the zig-zag mechanism. It moves about 2mm for the whole 6mm sitch width. 

I better say right now that i've got little knowledge on stepper motors or electronics in general, but looking at the Numbers of the steppers used in sewing machines (I found some part numbers, PM42L-048-HHC9 to be specific) against the usual hobby CNC nema stuff it seems they have less steps per revolution but alot more holding torque. Most sewing machines i've found photos/ videos of being disassembled gear the motors down, which seems sensible with that 2mm of travel.

Also am I right to assume that any bipolar stepper motor driver with the right current & voltage rating would run any bipolar stepper motor? I've got a bunch of drivers hanging about. Lyn sent me a few and i've got some A4988s from the 3d printer adventure.

[efrench]

. . . all very well but can a NEMA17 stepper motor keep up with that step rate, that was the point at issue 

The linked site has a few videos of one doing just that. 

[efrench]

Also am I right to assume that any bipolar stepper motor driver with the right current & voltage rating would run any bipolar stepper motor? I've got a bunch of drivers hanging about. Lyn sent me a few and i've got some A4988s from the 3d printer adventure.

This spreadsheet may be of some use.